s3-eventbridge-terraform: Update AWS Provider to v6

[kakakakakku]

Issue #, if available:
N/A

Description of changes:
Hi😀 Thanks for the useful patterns!

To keep this pattern maintainable, I updated the AWS Provider to v6.

Check

terraform apply completed successfully and works good.

$ terraform --version
Terraform v1.14.9
on darwin_arm64
+ provider registry.terraform.io/hashicorp/aws v6.41.0

$ terraform apply

#
# snip
#

Apply complete! Resources: 6 added, 0 changed, 0 destroyed.

Outputs:

EventBridge-Rule-Name = "terraform-20260607050737359000000003"
S3-Bucket = "serverlessland-terraform-s3-eventbridge-000000000000"
SNS-Topic-ARN = "arn:aws:sns:us-east-1:000000000000:terraform-20260607050733168600000002"

$ aws s3 cp README.md s3://serverlessland-terraform-s3-eventbridge-000000000000 --region us-east-1
upload: ./README.md to s3://serverlessland-terraform-s3-eventbridge-000000000000/README.md

Thank you😀

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[parikhudit]

Optional: jumping ~> 3.27 → ~> 6.0 skips v4 and v5. The Terraform v6 upgrade guide recommends stepping through the latest 5.x first. None of the resources used here seem to have v6 breaking changes, so for fresh deployments this works. However, please confirm in the PR description that you've run terraform init && terraform apply against ~> 6.0 end-to-end.

[kakakakakku]

@parikhudit
Thanks for the review!

I believe the patterns in this repository are mainly intended for builders to try out and then tear down shortly after. So I don't think we need to be as strict about stepping through major versions as we would in a production environment.

For this PR, I've confirmed the pattern works end-to-end with AWS Provider v6. I had already attached the verification logs in the PR description from the beginning, and I've now also added the terraform --version and terraform apply logs as well.

How does that look?
Thanks👍

[parikhudit]

Thanks for bumping up the dependency versions, @kakakakakku!